A thermal barrier can be a material positioned to prevent the transfer of heat across a temperature gradient. In some instances, a thermal barrier can include a coating applied to the surface of a substrate to minimize the migration of heat into, or out of, the substrate. In different uses, thermal barriers can include solids, such as organic polymers or inorganic oxides or other ceramics, liquids, gases, or combinations thereof.
A thermal barrier's ability to minimize heat transfer is generally a function of the material's thermal conductivity: the lower the thermal conductivity, the greater the extent to which heat transfer will be minimized. Thermal conductivity is generally a function of the composition and structure of the material and, in many instances, there is no easy way to modify, or tune, the thermal conductivity of a given thermal barrier material, to suit the needs of a particular application.
Nanolayered materials generally are materials that naturally adopt a structure having stacks of two-dimensional crystallites: sheets of the material that can be macroscopic in length and/or width, but have thickness in the low nanometer scale. Such materials have been used as solid lubricants, as electrode materials, and for a number of other electrical or optical uses. It has been shown that electrochemical and other properties of nanolayered materials can be adjusted by intercalation with small molecules or ions.